Eccentric drive for a portable handheld work apparatus

Abstract

The invention relates to an eccentric drive ( 1 ) and especially to an eccentric drive for a portable handheld work apparatus having a wheel ( 3 ) driven by a drive motor ( 2 ). A cam ( 5 ) is eccentrically fixed to an end face ( 4 ) of the wheel ( 3 ). The cam ( 5 ) is held by a connecting rod ( 6 ) and cylinder-shaped roller bodies ( 7 ) are mounted between the connecting rod ( 6 ) and the cam ( 5 ). The roller bodies ( 7 ) have axial ends ( 8 ) which engage in an annular slot ( 9 ) of the wheel ( 3 ). A holding element ( 11 ) is disposed on the cam ( 5 ) and limits the axial play of the roller bodies ( 7 ).

What is claimed is:  
     
       1. An eccentric drive for a work apparatus, the eccentric drive comprising: 
       a wheel defining a rotational axis and having an end face;  
       a cam fixedly mounted eccentrically on said end face so as not to be rotatable relative to said wheel;  
       a drive motor for driving said wheel to rotate about said rotational axis;  
       a connecting rod having a connecting rod eye for receiving said cam therein so as to cause said connecting rod eye and said cam to conjointly define an interface therebetween;  
       a plurality of roller bodies disposed at said interface to define a roller bearing between said cam and said connecting rod eye;  
       said wheel having an annular slot disposed in surrounding relationship to said cam;  
       each of said roller bodies having a first axial end engaging said annular slot;  
       a holder having an edge and being fixed on said cam;  
       each of said roller bodies having a second axial end adjacent said holder; and,  
       said roller bodies projecting radially beyond said edge of said holder.  
     
     
       2. The eccentric drive of  claim 1 , said annular slot having a depth; the second axial end of each of said roller bodies and said holder conjointly defining a space therebetween; and, said depth being greater than said space. 
     
     
       3. The eccentric drive of  claim 2 , said slot having a width and each of said roller bodies having a diameter; and, said width being greater than said diameter. 
     
     
       4. The eccentric drive of  claim 3 , wherein said cam has an end face and said holder is fixed to said end face of said cam. 
     
     
       5. The eccentric drive of  claim 4 , wherein said holder is spot-weld connected to said cam. 
     
     
       6. The eccentric drive of  claim 1 , wherein said holder is circularly shaped. 
     
     
       7. The eccentric drive of  claim 6 , wherein said holder has an annular shape. 
     
     
       8. The eccentric drive of  claim 1 , wherein said holder is made of spring steel. 
     
     
       9. The eccentric drive of  claim 1 , wherein said cam and said wheel are formed as a single piece. 
     
     
       10. The eccentric drive of  claim 1 , wherein said drive motor has a drive shaft with a pinion mounted thereon so that said pinion cannot rotate relative to said shaft; and, said wheel is a toothed wheel in meshing engagement with said pinion. 
     
     
       11. The eccentric drive of  claim 10 , wherein said connecting rod is in gliding contact engagement with an end face of said toothed wheel. 
     
     
       12. The eccentric drive of  claim 1 , wherein said work apparatus is a hedge trimmer.